/*
 *  Command-line arguments are options if they begin with a hyphen ('-')
 *  Multiple options may follow a hyphen in a cluster if they do not take arguments. Thus, '-abc' and '-a -b -c' are the same
 *  Option names are single alphanumeric characters
 *  Options may require an argument. For example, the '-o' option of the ld command requires an output file name
 *  The whitespace separating an option and its argument is optional. Thus, '-o foo' and '-ofoo' are the same
 *  Options usually precede non-option argument. (In fact, *argp* is more flexible than this; if you want to suppress this flexbility, define the _POSIX_OPTION_ORDER enviroment variable)
 *  The argument '--' terminates all options; all following command-line arguments are considered non-option arguments, even if they begin with a hyphen
 *  A single hyphen as an argument is considered a non-option argument; by convention, it is used to specify input from standard input or output to standard output
 *  Options may appear in ayn order, enven mutiple times. The meaning of this is left to the application
 *  Long options can accept optional (that is, non-necessary) argument. You can specify an argument for a long option as follows: --option-name=value
 */
